Setup a Target Root

mkdir -p ~/arm-cross/dest
cd arm-cross

Build protobuf

Wheezy comes with 2.4.1 which is a pain since you need to generate the protobuf headers with the same version as you compile against. Either use the 2.4.1 version or build 2.5.0 locally (but don't install).

tar -zxf protobuf-2.5.0.tar.gz
mv protobuf-2.5.0 protobuf-2.5.0-native
cd protobuf-2.5.0-native
./configure
make
pwd # make a note of this, you need it for the --with-protoc option below